Typically, a cutting machine for stone materials comprises a power head part, a bedplate, a frame for supporting the bedplate and a basin disposed under the frame. The frame is equipped with a guide rail for the bedplate to slide on. When performing a cutting operation, a work piece to be cut is placed on the bedplate and the bedplate is then moved toward the power head part to perform the cutting operation. The basin has a bottom surface and an upright wall around the periphery of the bottom surface, and receives water therein such that dust and noise pollution during the cutting operation is decreased and is therefore beneficial in protecting the environment and the workers' health. At the same time, the water in the basin also is used to lubricate, cool and decontaminate the saw blade of the power head part to increase the usable life of the cutting tool. In order to further maintain the cleanliness of the environment while not increasing the surface area of the basin, an expanded basin may be provided at a separate position out of the basin. The expanded basin of the cutting machine for stone materials in the prior art extends horizontally in a certain direction or around the circumference of the main basin for receiving water drops or water fog that is splattered out of the main basin. Generally, the orientation of the expanded basin is in accordance with that of the bedplate and is immovable relative to the bedplate. Due to the limitation of assembled angle and size of the expanded basin, the ability to receive the splashed polluted water is poor, which results in pollution of the working environment. To reduce the splashed water, it is generally desired to have a larger expanded basin or to add other devices.